Metering method for supplying detergent concentrate

ABSTRACT

A method and apparatus for supplying dry detergent concentrate to a metering device for dissolving or dispersing in water which prevents or minimizes the formation of dust, lumping, caking, and encrustation of vessel walls and supplies new detergent to the laundry plant in response to changes in electrical conductivity of the wash water from a predetermined value which indicates consumption of original detergent required in soil removal and need for replenishment thereof. The minimizing of dust and protection of the detergent from moisture is accomplished by using a flexible delivery container, the filling means and emptying means of which are sealable and which emptying means acts in cooperation with the metering apparatus section to form an integral delivery system which is generally isolated from the surrounding atmosphere.

BACKGROUND OF THE INVENTION

The present invention concerns a metering method and apparatus forsupplying a commercial washing apparatus or laundry with water-solubleor water insoluble powdered or granulated detergent concentrate from adelivery container to the storage bin of the metering apparatus whereportions of the detergent are dissolved in or mixed with water and thenconveyed to the commercial washing machine or laundry.

The terms "washing machine" and "detergent" are understood to be usedhere in a general sense and are understood to comprise rinsing andcleaning machines and rinsing and cleaning agents respectively.

The metering methods presently employed in supplying detergents has anoperator fill the storage bin of the metering device by hand from thedelivery container. The metering devices are electrically orpneumatically driven and operate with water as a conveying and/orsolvent medium for the detergent. In some methods the detergent ismetered to the wash water by hand, simply so much per given time.Another metering device uses the conductivity of the wash water anddetergent added when change beyond a predetermined point occurs. Thepowdered or granulated material is constantly fed into a hopper where itis mixed with water and flows from the latter by gravity feed into thelaundry wash water (see German Pat. No. 1,542,298). There are alsodevices where the replenishment of detergent is simply a function oftime. A given weight of detergent is mixed with water and added to thewash water by pumping it to the washing machine. Finally meteringdevices are presently used which flush detergent from the storage binwith water and the resultant mixture conveyed to the washing machine bymeans of a pump or by gravity feed.

A disadvantage of the known detergent metering methods and apparatus isin most cases the formation of dust during the filling of the storagebin on the metering device. Furthermore, the hygroscopic detergent isexposed during the open transportation to the high humidity of thesurrounding air, which can lead to lumping and caking. The lifting andtransportation of relatively heavy delivery containers (e.g., paper bagsof about 55 lbs.) used in the operation of commercial washing machinesrepresents a considerable burden for the operators, particularly in thecase of large consumers with a daily requirement of several hundred lbs.of detergent. In the presently used devices with time-dependentmetering, where there is no indication of the concentration used, theamount of detergent required, which may be higher or lower depending onthe degree of soiling, is not taken into account. The flushing of thedetergent from the storage bins with water leads frequently to lumpingand encrustation, which can make more difficult or prevent theconveyance of the mixture.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a metering method andapparatus for supplying detergent to a commercial laundry.

Another object of the present invention is to provide a means fortransferring powdered or granular detergent from the container in whichit is supplied to the storage bin of the metering device withoutcreating significant dust.

A further object of the present invention is to provide a deliverycontainer capable of protecting the detergent from exposure to wetnessand high humidity until it is delivered to the storage bin of themetering device prior to mixing it with water.

Another object of the present invention is to provide a method andapparatus by which powdered or granular detergent is transferred from adelivery container to a storage bin of a metering device withoutcreating dust, said detergent being protected from wetness and highlyhumid air from its arrival at the laundry plant until its mixture withwater prior to adding the mixture to the wash water.

These and other objects of the invention will become more apparent asthe description thereof proceeds.

THE DRAWING

The drawing is a schematic representation of one embodiment of thepresent invention.

DESCRIPTION OF THE INVENTION

The present invention concerns a metering method and apparatus by meansof which a powdered or granular detergent concentrate is conveyed from astorage bin to a metering device where it is transformed, preferablyunder controlled addition of water as a conveying medium and/or solventin a fixed ratio by weight, into a pumpable mixture. The aqueousdetergent mixture is then transferred by means of a pump into thecommercial laundry plant, the amount of said aqueous detergent providedbeing dependent on a predetermined value of the electrical conductanceof the aqueous detergent wash solution in the commercial laundry. Thedetergent, even when not soluble in water, is at least partly dissolvedin the conveying medium.

A device for carrying out the method is characterized according toanother feature of the invention by the apparatus comprising apreferably flexible delivery container for the powdered or granulardetergent concentrate which can be suspended above the storage bin ofthe metering device, and the connection of the delivery container withthe storage bin by means of a pour hole which empties through aflexible, closable channel between the bottom of the delivery containerand the head of the storage bin.

By means of the method and arrangement for carrying out the method it ispossible to move the detergent supply, e.g., of a commercial washingmachine under conditions which are dust-free and without any substantialrisk of lumping or caking or encrustation of the vessel walls by thedetergent. Particularly when using a delivery container with an openingat the bottom, and a constrictable channel leading to the storage bin ofthe metering device and having a suspension means for the deliverycontainer, physical strain can be substantially avoided by using liftingdevices, like fork lifts.

The detergent concentrates to be metered according to the inventioncomprise soluble and insoluble products, including those detergents orwashing aids, such as perborate which can not be metered in liquid formas stock solutions, because of their chemical reaction.

The schematic drawing represents one of the preferred embodiments of thepresent invention showing the spatial relationship between parts and thegeneral features of an apparatus in which the present invention can becarried out.

The powdered or granular detergent 1 is supplied in delivery container2. The capacity of said container may range up to several hundredpounds. The delivery container 2 preferably consists of a suitable,strong, flexible material such as plastic coated fiber mat, or of paper,having a closable filling means 3 and an emptying means 4, the flow fromwhich can be stopped by constricting of the tubular canal 10 which maybe attached to the delivery container or may be molded as a partthereof. The delivery container 2 may have a polygonal or a round base.

The filled delivery container 2 is attached to supporting frame 6 bymeans of lugs 5 provided on its upper surface and adapted to cooperatewith hooks 5a attached to supporting frame 6. It is positioned abovemetering device 7 in a mount 8. Delivery container 2 can be placed intoposition for suspension by means of a fork-lift or chain hoist with aguide rail at a place above the metering device 7 on supporting frame 6held up by mount 8.

The filling of storage bin 9 on metering device 7 is effected over pourhole 4 and tubular canal 10. The latter can be closed by constricting itin the manner indicated by broken lines. The supply of the powder orgranular material 1 from delivery container 2 stops automatically whensaid material forms pouring cone 11 and fills the entire cross sectionof the opening of tubular canal 10. Flow starts again when detergent 1is taken from storage bin 9 and the opening of canal 10 iscorrespondingly cleared.

During the metering, that is, after the drive of metering device 7 hasbeen turned on, detergent 1 trickles continuously over a rotatingsprinkling disk 12 into a flushing hopper 13, where it is transformed toa pumpable mixture by the addition of water from a water supply 14. Themixture is fed by means of pump 15 into washing tank 16 of washing plant17.

The detergent concentration of laundering, wash water solution 18 inwashing tank 16 is transformed in the embodiment by a measuring probe 19into an electrical signal, and transmitted to an electrical control 20.Control 20 should preferably contain several program options. When theactual value of the detergent concentration drops below the pre-setvalue in the selected program of electronic control 20, this istransmitted correspondingly over line 21, metering device 7 isactivated, meters detergent-water mixture to the laundering wash wateruntil this pre-set value has been reattained and then shuts off. Allparts to be controlled, e.g., sprinkling disk 12, the amount of water,pump 15 and storage vessel 9, if necessary, are effected by control 20over line 21, corresponding to the requirements. Different pre-setconcentration values can be transmitted in the latter over line 22depending on the cleaning requirements of washing plant 17.

In connection with metering device 7 and when using a flexible deliverycontainer 2 with an emptying means 4 at the bottom, delivery ofdetergent can be effected directly from the latter during the operationof the metering device. The volume of delivery container 2 can be amultiple of the volume of storage bin 9 on metering device 7. Theflexibility of delivery container 2 ensures complete emptying with acorresponding design, without the necessity of operating on the pouredmaterial mechanically. Tubular canal 10 adjoining emptying means 4, andfill hole with a suitable diameter in storage bin 9 of metering device 7cooperate to prevent the formation of dust in the vicinity of theapparatus. This dust protection at the same time acts as a seal againstthe penetration of usually humid air of the work place into the interiorof the delivery container, tubular canal, or storage bin. Prematureabsorption of moisture by the detergent is therefore prevented. Afterconstricting or tying-off tubular channel 10 at the boundary to emptyingmeans 4, delivery container 2 can be separated from metering device 7.Delivery container 2 is at this point hermetically sealed.

When using a supporting frame 6 for the suspension of delivery container2, it is possible to move and lift the container by means of a fork liftor chain hoist with guide rail thereby relieving the operators of heavyphysical work. Large delivery containers, which are designed to bereusable, can be returned after emptying to the detergent manufacturerfor re-filling.

By continuously measuring the concentration of laundering solution 18 itis possible to determine the actual need of detergent at any time.Detergent addition is effected according to the invention only when theconcentration drops below the predetermined value of the launderingsolution. The detergent consumption is thus directly related to thedegree of soiling of the parts or fabrics to be cleaned.

The preceding specific embodiments are illustrative of the practice ofthe present invention. It is to be understood, however, that variationswhich may be obvious to those skilled in the art or suggested herein,may be employed without departing from the spirit of the invention orthe scope of the appended claims.

We claim:
 1. A method for supplying measured amounts of water soluble orwater insoluble powdered or granular detergent concentrate to acommercial washing machine or laundry which comprises suspending adelivery container having a pour hole at its bottom above a storagemeans in a metering device having a rotating disk upon which detergentconcentrate from the storage means falls; connecting a substantiallydust-tight tubular closable channel from the bottom of said deliverycontainer to the top of said storage means; providing detergentconcentrate to said delivery container; closing and opening saidclosable channel to cause some or all of said detergent concentrate tomove by gravity feed through said pour hole and said channel to saidstorage means; and metering the supply of said detergent concentrate bycausing said detergent concentrate to move by gravity feed from saidstorage means onto the rotating disk and then into a hopper situatedbelow said rotating disk, adding water to said hopper, mixing saiddetergent concentrate with said water in a predetermined ratio in themixing means whereby said water acts as a solvent and/or conveyingmeans, and pumping the resulting detergent concentrate-water mixture tothe commercial washing machine or laundry, the moving of concentrate bygravity feed, adding of water, and pumping being activated in responseto changes in a predetermined value in the electrical conductance of thewash water in the commercial washing machine or laundry.
 2. A method asset forth in claim 1 wherein the degree of depletion of wash waterdetergent is measured as a function of its conductivity anddetergent-water mixture added when conductivity varies more than apredetermined value.